1. Field of the Invention
The present invention relates to an electromagnetic relay and, more particularly, to an electromagnetic relay having a double armature structure.
2. Prior Art Statement
FIG. 6 is a perspective view of a conventional electromagnetic relay of the double pole type. In this electromagnetic relay, an electromagnet 52 is attached to a standing portion 51a of a yoke 51 over a base 50. One armature 53 is pivotably supported by a hinge to the edge of a front projecting portion 51b formed at the upper portion of the yoke 51. When a current is supplied to the electromagnet 52, the armature 53 is attracted to the electromagnet 52 and is rotated, so that contacts of both of right and left contact mechanisms 55 are closed. On the contrary, when the current supply to the electromagnet 52 is stopped, the armature 53 is rotated and returned by a return spring 54, so that both of the contact mechanisms 55 are open.
However, in such an electromagnetic relay, if one of the contact mechanisms 55 is not opened because, for example, the contacts were fused and bonded, the other contact mechanism 55 is also held in the closed state. Therefore, as shown in FIG. 7, when such contact mechanisms 55 are used as a double pole single throw switch in a power supply circuit of an electric apparatus 56, there is a problem such that even if the operator desires to disconnect the power supply circuit, a current continuously flows through the electric apparatus 56 by the foregoing melt-bonding of the contacts.
On the other hand, as shown in FIG. 8, if two electromagnetic relays of the single pole type each using one contact mechanism 55 in the electromagnetic relay shown in FIG. 6 are used, the foregoing problem can be solved. However, in this case, there is a problem of an increase in cost. A constitution of FIG. 8 is similar to that of FIG. 6 except a different point such that one of the contact mechanisms 55 in FIG. 6 is omitted, so that the same parts and components as those shown in FIG. 6 are designated by the same reference numerals and their descriptions are omitted.